Messages in this thread | | | From | Patrick Bellasi <> | Subject | Re: [PATCH 1/2] sched/uclamp: Add a new sysctl to control RT default boost value | Date | Fri, 15 May 2020 13:08:29 +0200 |
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I Qais, I see we are converging toward the final shape. :)
Function wise code looks ok to me now.
Lemme just point out few more remarks and possible nit-picks. I guess at the end it's up to you to decide if you wanna follow up with a v6 and to the maintainers to decide how picky they wanna be.
Otherwise, FWIW, feel free to consider this a LGTM.
Best, Patrick
On Mon, May 11, 2020 at 17:40:52 +0200, Qais Yousef <qais.yousef@arm.com> wrote...
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> +static inline void uclamp_sync_util_min_rt_default(struct task_struct *p, > + enum uclamp_id clamp_id) > +{ > + unsigned int default_util_min = sysctl_sched_uclamp_util_min_rt_default; > + struct uclamp_se *uc_se; > + > + /* Only sync for UCLAMP_MIN and RT tasks */ > + if (clamp_id != UCLAMP_MIN || !rt_task(p)) > + return; > + > + uc_se = &p->uclamp_req[UCLAMP_MIN];
I went back to v3 version, where this was done above:
https://lore.kernel.org/lkml/20200429113255.GA19464@codeaurora.org/ Message-ID: 20200429113255.GA19464@codeaurora.org
and still I don't see why we want to keep it after this first check?
IMO it's just not required and it makes to code a tiny uglier.
> + > + /* > + * Only sync if user didn't override the default request and the sysctl > + * knob has changed. > + */ > + if (uc_se->user_defined || uc_se->value == default_util_min) > + return; > +
nit-pick: the two comments above are stating the obvious.
> + uclamp_se_set(uc_se, default_util_min, false); > +} > + > static inline struct uclamp_se > uclamp_tg_restrict(struct task_struct *p, enum uclamp_id clamp_id) > { > @@ -907,8 +949,13 @@ uclamp_tg_restrict(struct task_struct *p, enum uclamp_id clamp_id) > static inline struct uclamp_se > uclamp_eff_get(struct task_struct *p, enum uclamp_id clamp_id) > { > - struct uclamp_se uc_req = uclamp_tg_restrict(p, clamp_id); > - struct uclamp_se uc_max = uclamp_default[clamp_id]; > + struct uclamp_se uc_req, uc_max; > + > + /* Sync up any change to sysctl_sched_uclamp_util_min_rt_default. */
same here: the comment is stating the obvious.
Maybe even just by using a different function name we better document the code, e.g. uclamp_rt_restrict(p, clamp_id);
This will implicitly convey the purpose: RT tasks can be somehow further restricted, i.e. in addition to the TG restriction following.
> + uclamp_sync_util_min_rt_default(p, clamp_id); > + > + uc_req = uclamp_tg_restrict(p, clamp_id); > + uc_max = uclamp_default[clamp_id]; > > /* System default restrictions always apply */ > if (unlikely(uc_req.value > uc_max.value))
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